Cam removing device for a sewing machine



July 29, 1969 L, J, COULOMBE 3,457,887

CAM REMOVING DEVICE FOR A SEWING MACHINE Filed Feb. 7, 1967 2 She et s-Sheet 1 Illllllllll lllllllmnlmlml I numu ..i' 1

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INVENTOR.

Lionel J. Coulombe Witness TTORNELW July 29, 1969 J. COULOMBE 7,

CAM REMOVING DEVICE FOR A SEWING MACHINE Filed Feb. 7, 1967 2 Sheets-Sheet 2 g INVENTOR. 7 Lionel J. Coulombe Witness BY 'flaiallnd 724' W y ATTORNEY United States Patent 3,457,887 CAM REMOVING DEVICE FOR A SEWING MACHINE Lionel J. Coulombe, Matawan, N.J., assignor to The Singer Company, New York, N.Y., a corporation of New Jersey Filed Feb. 7, 1967, Ser. No. 614,432 Int. Cl. Db 3/02 US. Cl. 112-158 7 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates to a zig-zag sewing machine having stitch forming instrumentalities operating responsive to a cam controlled actuating mechanism. More particularly, the disclosure relates to a cam releasing device that operates to release the cam from its detachable connection to the cam shaft.

Background of the invention In a zig-zag sewing machine it is common practice to control the movement of various mechanisms, such as the lateral vibration of the needle-bar, responsive to a predetermined pattern formed on the surface of a cam. The cam may be fixedly connected by screws to the cam shaft, but this has the disadvantage of requiring removal and reconnection of the screws each time a new cam pattern is inserted. It is more convenient to detachably connect the cam to the cam shaft by yieldable means such as springs and the like. However, the cam must be securely mounted and this ofttimes makes its substitution diflicult, especially if it is located in a place of limited access. Heretofore the cam could be removed by the use of an integrally mounted spring loaded platform which coacted with a second device operating on the yieldable means. It is apparent that such a release mechanism, in addition to being costly and complex, would act as a design limitation of the construction of the yieldable means that detachably connect the cam to the cam shaft.

Summary of the invention In accordance with the present invention the novel releasing device includes a cam releasing member connected to the frame of the sewing machine. A cam engaging portion is formed on said member to be normally out of engagement with the cam. Means is connected to said member for shifting the cam engaging portion into engagement with the cam responsive to operator influenced movement of the cam releasing member to detach the cam from the clamping means and unseat the cam from the cam shaft.

It is therefore an object of the present invention to provide an improved cam releasing device for a sewing machine which overcomes the prior art disadvantages; which is simple, economical and reliable; which may be manually operated; which facilitates the substitution of the cam regardless of its accessability; which uses a cam releasing member that is shiftable to force the cam to unseat from its detachably clamped mounting on the cam shaft; which uses a cam releasing member including a lever means that is pivotally connected to the frame so that on rotation thereof it will force the cam disc to be unseated from its detachably clamped mounting on the cam shaft; which uses a lever means that has an arcuate finger adapted to engage a large portion of the under side of the cam on raising the lever means to increasingly urge the cam to unseat from its detachable connection to the cam shaft; which uses a lever means that is connected on one side of the arm shaft and has an arcuate finger extending across the arm shaft.

Other objects and advantages will be apparent from the following description of one embodiment of the invention and the novel features will be particularly pointed out hereinafter in the claims.

Brief description of the drawings This invention is illustrated in the accompanying drawings in which:

FIGURE 1 is a front elevational view of a sewing machine with the casing broken away and partly in section of a sewing machine embodying the present invention with the novel cam releasing member being shown in inoperative position,

FIGURE 2 is an enlarged perspective view partly in section of the cam access opening in the casing showing the novel cam releasing member in the same position as shown in FIGURE 1,

FIGURE 3 is an enlarged perspective view, partly in section, showing the novel cam releasing member operating to cause the cam to be released from the yieldable means which releasably clamp it to the cam shaft,

' FIGURE 4 is an enlarged exploded view of the novel cam releasing member in inoperative position adjacent the cam shaft with the cam in superposition thereto, and

FIGURE 5 is an enlarged exploded view of the cam assembly as seen from the opposite side of FIGURE 4.

Description of the invention In the illustrated embodiment of the invention the sewing machine may be of any conventional type having stitch forming instrumentalities therein; see for example US. Patent No. 3,051,107, Aug. 28, 1962, R. E. Johnson, Zig- Zag Sewing Machine. Accordingly, FIGURE 1 shows a frame 8 of a sewing machine having a bed 10 from one end of which is a vertically extending standard 12 having connected thereto a cantilevered bracket arm 14 that terminates in a head 16 overhanging the bed 10.

Stitch forming instrumentalities are disposed in frame 8 and include a needle 11 clamped to needle bar 13 for vertical reciprocation and lateral vibration therewith.

The sewing machine has suitable actuating mechanism for the stitch forming instrumentalities of which, an arm shaft 18 is journaled longitudinally in bracket arm 14 and has a worm gear drive 20 mounted intermediate its ends, with one of the ends of arm shaft 18 disposed in standard 12 and connected to a source of rotatable power (not shown).

Included in the actuating mechanism is a cam assembly referred to briefly herein and substantially the same as that shown and described in US. Patent No. 3,057,311, Oct. 9, 1962, R. E. Johnson, Cam Mounting Means for Zig-Zag Sewing Machine.

The cam assembly has a vertical axis stud 22, illustrated in FIGURES 1, 4 and 5, mounted in bearing boss 24 of bracket arm 14. Stud 22 has a mounting portion 26 that is disposed in a bore 28 of boss 24. A section 26a of smaller diameter than mounting portion 26 is disposed intermediately thereof and adapted to receive a set screw (not shown) to secure stud 22 in boss 24.

Iournaled on stud 22 immediately above boss 24 is a tubular cam shaft 30 having worm wheel 32 formed integrally thereon at the lower end thereof, which wheel 32 is adapted to engage worm gear drive 20 to cause cam shaft 30 to rotate on rotation of arm shaft 18.

Cam shaft 30 shown in FIGURES 4 and 5 has a frustoconical top section 34 the base of which terminates in an outwardly extending annular flange 36. A second flange 38 is formed below and in spaced relation to flange 36, with groove 40 disposed therebetween. A semi-circular slot 42 is formed at the lower end of groove 40 and the upper end of flange 38 extending from near the center of the cam shaft outwardly thereof. Annular groove 46 is formed near the upper end of stud 22 and in assembled position will be in substantial alignment with slot 42. A key 48 is disposed in slot 42 to seat on the recessed top surface 49 of flange 38 and has its edge 51 abut shoulder 53 formed at the inner side of slot 42. Key 48 extends into engagement with groove 46 to maintain the rotatable connection between cam shaft 30 and stud 22. Holes 50a and 50b are formed in flanges 36 and 38, respectively, in alignment with each other and adapted to receive a pin 52 that extends therethrough and passes through hole 500 in key 48 formed in alignment with holes 50a and 50b. Pin 52 looks key 48 in position, and has its upper end 52a extending above the upper surface 54 of flange 36.

The frusto-conical section 34 has three equidistantly spaced recesses 56 extending vertically from its top surface 58 to below the upper surface 54 of flange 36. A threaded hole 60 is formed at the center of the top surface 58.

A cam support spring 62 has a hub 64 with a central hole 66 and an outer edge 68 from which three equally spaced downwardly extending resilient prongs 70, 70 and 70 extend. Each of the three prongs 70 of spring 62 has a short radially extending section 72 that bends downwardly into a vertical section 74 that bulges outwardly at mid-section 76. Spring 62 is mounted on frustoconical section 34 by a screw 79 passing through hole 66 of hub 64 to be threadedly engaged in hole 60 on the top 58 of section 34. Prongs 70 are disposed in recesses 56 with the lower ends of vertical sections 74 extending below the seating surface 54 of flange 36, and the bulge at midsection 76 extending radially outwardly from the outer surface of section 34.

A cam 78 has a central hole 80 from which extends a radial slot 82. A suitable pattern surface 84 is formed on the periphery of cam 7 8. The cam 78 is detachably clamped to cam shaft 30 by seating it on the upper surface 54 of flange 36 with pin end 52a disposed in the radial slot 82 so as to angularly lock the cam 78 in position relative to cam shaft 30. Of course cam 78 is disposed on section 34 with suflicient downward force to deform the bulge section 76 of prongs 70 to permit the seating of the under surface 86 of cam 78 on upper surface 54 of flange 36. The detachably clamped position of cam 78 is maintained by the bulge section 76 of spring 62 urging the cam 78 against seating surface 54 in the preset angular position established by pin 52.

Actuating linkage 88 terminating in a contact finger 90 that engages the pattern surface 84 to move responsive thereto to regulate the sewing machine stitch forming instrumentalities in a manner well known in the art.

Standard 12 and bracket arm 14 have an open top over which is connected a top cover plate 92 having an access opening 93 adjacent cam shaft 30 and cam 78. A hinged plate 94 normally covers access opening 93 and is adopted to be swung away to expose access opening 93.

The cam removing device includes a cam releasing member or lever means 100 shown in FIGURES 1 and 4 with a vertical leg 102 that is pivotably connected to the frame 8 by its lower end being mounted to the shank of a screw 104 that passes through hole 106 prior to its being threadedly engaged by nut 108. Leg 102 is disposed in a normally vertical plane and has the upper end thereof turned inwardly to form a cam engaging means 109 that includes a horizontal leg 110 the outer end of which terminates in an arcuate finger 112. An upwardly extending handle 114 is bent to connect to the underside of horizontal leg 110 by spaced rivets 116. The vertical leg 102 is connected on the inside front wall of the frame on the right side of cam shaft 30. Horizontal leg 110 extends across cam shaft 30 to the left side thereof and has its arcuate finger 112 curving around and spaced from flange 36.

Leg 110 and arcuate finger 112 will normally lie in a horizontal plane slightly below the seating surface 54 of 4 flange 36 so as not to interfere with the normal operation of cam shaft 30 or cam 78. Also, as shown in FIGURES 2 and 3 the opening between the tip of finger 112 and leg 110 is sufficiently large that lever means never will interfere with contact finger 90.

In its detachably clamped position on cam shaft 30 cam 78 will have its outer edges and pattern surface 84 overhanging the periphery of seating surface 54. The outer diameter of arcuate finger 112 is the same or slightly larger than the outer diameter of cam 78 but the center of its curve will be located to the left of the axis of cam shaft 30 so that when lever means 100 is in the inoperative position shown in FIGURES 1 and 2 the left-most end of arcuate finger 112 will be disposed under and spaced away from pattern surface 84.

The cam removing device is operated as shown in FIG- URE 3 by shifting or swinging handle 114 upwardly. The affect is to rotate lever means 100 about its pivoted connection so as to increasingly tilt leg and arcuate finger 112 which are brought into engagement with the under surface 86 of cam 78 to come into increasing contact therewith and force cam 78 upwardly past the yieldable spring section 76 to thus be unseated from cam shaft 30.

The rotation of lever means 100 about its pivotable connection acts to tilt leg 110 and arcuate finger 112 at an ever increasing angle with the plane in which cam 78 normally lies in its detachably clamped position on seating surface 54. Increasing the angle serves a dual function of first bringing the left most edge of arcuate finger 112 into increasing engagement with the under surface 86 of cam 78, and secondly by forcing the cam 78 to tilt in a plain corresponding to that of the leg 110 and arcuate finger 112 less total force will be required to unseat the cam 78 because only a part of the resistant spring force of spring 62 is encountered initially.The horizontal distance between the pivotable connection and hole 106 and the handle 114 will create a sufficient moment arm so that only a minimum lifting force will be required to tilt cam 78 and raise upwardly to unseat from its detachable clamped position on cam shaft 30.

Though only one cam disc has been shown or described, it is Within the scope of the present invention to provide for the cam removing device to operate on a plurality of cams individually or interconnected.

It will be understood that various changes in the details, materials, arrangements of parts and operating conditions which have been herein described and illustrated in order to explain the nature of the invention may be made by those skilled in the art within the principles and scope of the invention.

Having thus set forth the nature of the invention, what I claim herein is:

1. A zig-zag sewing machine comprising:

(a) a frame,

(b) a stitch forming instrumentality disposed in the frame,

(c) actuating mechanism including a cam shaft disposed in the frame to operate the stitch forming instrumentality,

(d) a cam detachably secured on the camshaft to actuate the actuating mechanism in the operation of the stitch forming instrumentalities,

(e) releasable clamping means carried by the cam shaft to detachably clamp the cam to the cam shaft,

(f) a cam releasing member including a lever means formed with a connecting section, a cam engaging section and a shifting means,

(g) the connecting section pivotally connected to the frame,

(h) the cam having the outer edge thereof overhanging the cam shaft,

(i) at least a portion of the cam engaging section disposed under the overhanging edge of the cam and normally out of engagement therewith, and

(j) the shifting means defining a handle extending from the lever means and adapted to turn the lever means about its pivot to bring the cam engaging section into engagement with and force the unseating of the cam.

2. The combination claimed in claim 1 wherein:

(a) the cam shaft having its axis disposed substantially vertical and having the cam releaseably clamped thereon in a plane substantially perpendicular to its axis, and

(b) the cam engaging section of the lever means formed in an arcuate finger and in the normal inoperative position the center of the finger disposed in spaced relationship to and on one side of the axis of the cam shaft, and on rotation of the lever means to the operative position of unseating the cam the cen ter of the finger being shifted toward the other side of the axis of the cam shaft.

3. The combination claimed in claim 2 wherein:

(a) the arcuate finger of the cam engaging section to normally lie in a substantially horizontal plane below the cam and force the cam to be released from its detachably clamped position on the cam shaft.

4. The combination claimed in claim 1 wherein:

(a) the connecting section and the handle each disposed on the same side of the cam shaft, and

(b) the cam engaging section in the operative position to extend from the connecting section and handle means across the cam shaft in a plane below that of the cam whereby on turning of the lever means th cam engaging section thereof to swing into increasing engagement with the cam and force the cam to be unseated from the cam shaft.

5. The combination claimed in claim 4 wherein:

(a) the cam engaging section extending in an arcuate path away from the handle means and about the cam, and

(b) the connecting section and the handle means disposed in a predetermined spaced relationship to each other to create a substantial moment arm whereby on turning of the lever means sufiicient force will be created to cause the cam to be unseated from the cam shaft.

6. The combination claimed in claim 1 wherein:

(a) the releasable clamping means including a spring having a plurality of prongs releasably clamping the cam to the cam shaft, and (b) the lever means being turned to increasingly tilt the cam engaging section into engagement with 5 and urge the tilting of the cam at an increasing angle to force the cam to be successively released from clamping engagement with the prongs of the spring whereby the cam will be unseated from the cam shaft.

7. A cam removing device for a sewing machine of the type having a frame, stitch forming mechanism carried in said frame, actuating mechanism for the stitch forming mechanism in the frame including a cam shaft having a free extremity, a cam detachably secured to the cam shaft, and releasable locking means on the cam shaft for retaining the cam on the cam shaft, said cam removing device comprising:

(a) a cam releasing member spaced from the cam shaft,

(b) a cam engaging portion formed on the cam releasing member and disposed at the opposite side of the inserted cam from the cam shaft extremity,

(c) means shiftably supporting and pivotally connecting the cam releasing member to the sewing machine frame for operator influenced movement of the cam engaging portion toward and away from the cam shaft extremity to selectively unseat the cam from the cam shaft, and

(d) the cam engaging portion formed on the end of the cam releasing member remote from the said pivotal connection thereof and disposed normally out of engagement with the cam, and on shifting of the cam releasing member said cam engaging portion adapted to swing into contact with the cam to force the cam to be unseated from the cam shaft.

References Cited UNITED STATES PATENTS RICHARD J. SCANLAN, JR., Primary Examiner 

